Pre-stressed concrete reinforced strand tensioning device



July 13, 1965 J. 5. SIMMS FEE-STRESSED CONCRETE REINFORCED STRANDTENSIONING DEVICE 5 Sheets-Sheet 1 Filed March 6, 1963 5 )INVENTOR.-

JAMES S. SIMMS I HIE-42H July 13, 1965 J1 s. SIMMS 3,194,536

PRE-STRESSED CONCRETE REINFORCED STRAND TENSIONING DEVICE Filed March 6,1963 s Sheets-Sheet 2 6 2/ 33 25 -54 as 77 @r '25 32 7 0 (f) (3r @7 l/ 7INVENTOR JAMES S. SMMS BYCMQM H15 HZ-L H- y 3, 1965 J. 5. SIMMS3,194,536

PRE-STRESSED CONCRETE REINFORCED Q STRAND TENSIONING DEVICE Filed March6, 1963 3 Sheets-Sheet 5 INVENTOR. JAMES S. sIMMS United States Patent3,194,536 PRE-TREED CQNCRETE RETNFGRGCED STRAND TENSEGNTNG DEVICE .iamesS. Simms, 5301 W. Patterson Ave, Chicago 41, Ill. Filed Mar. 6, 1963,Ser. No. 263,182 Claims. (Cl. 254-29) This invention relates totensioning units and, more particularly, to tensioning units which areparticularly well adapted for tensioning cables used in pro-stressedconcrete, and the like.

It is a primary object of the present invention to afford a noveltensioning unit for tensioning cables and the like.

Devices have been heretofore known in the art for tensioning cables inthe production of pre-stressed concrete, and the like. However, suchdevices as have been heretofore known in the art have had severalinherent disadvantages such as, for example, being large and cumbersomein size; being difficult and complicated in construction and operation;not being reliable in operation; being expensive to manufacture; or notbeing readily portable, and the like. It is an important object of thepresent invention to overcome such disadvantages.

Another object of the present invention is to afford a novel tensioningdevice of the aforementioned type which is relatively small and compactin size.

Another object is to aiford a novel tensioning device of theaforementioned type which is readily transportable.

Yet another object is to afford a novel tensioning device of theaforementioned type which may be quickly and easily attached to a cableto be tensioned, and which may be quickly and easily released from sucha tensioned cable.

A further object is to afford a novel tensioning device of theaforementioned type which is relatively simple in construction, and yetis practical and reliable in operation.

Another object is to afford a novel tensioning device of theaforementioned type which is practical and efficient in operation, andwhich may be readily and economically produced commercially.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, by way of illustration, show a preferredembodiment of the present invention and the principles thereof and WhatI now consider to be the best mode in which I have contemplated applyingthese principles. Other embodiments of the invention embodying the sameor equivalent principles may be used and structural changes may be madeas desired by those skilled in the art without departing from thepresent invention and the purview of the appended claims.

In the drawings:

FIG. 1 is a fragmentary perspective view of a tensioning unit embodyingthe principles of the present invention, showing the unit disposed inoperative position relative to a cable to be tensioned;

FIG. 2 is a top plan view of the tensioning unit shown in FIG. 1;

FIG. 3 is a fragmentary longitudinal sectional view taken substantiallyalong the line 33 in FIG. 2;

FIG. 4 is a fragmentary top plan view of a portion of the unit shown inFIG. 2, with certain parts disposed in different operative position;

FIG. 5 is an elevational view of the unit shown in FIG. 1, looking inthe direction of the arrows 5-5 in FIG. 2;

FIG. 6 is a transverse sectional View taken substantially I along theline 6-6 in FIG. 2;

FIG. 7 is a transverse sectional view taken substantially along the line77 in FIG. 2;

FIG. 8 is an end elevational view of the chuck embodiedin the transferunit shown in FIG. 1;

FIG. 9 is a longitudinal sectional view taken substantially along theline 99 in FIG. 8;

FIG. 10 is a longitudinal sectional view similar to FIG. 9, but showingcertain parts in different operative position; and

FIG. 11 is a transverse sectional view taken substantially along theline 11-41 in FIG. 9.

A tensioning unit 1 embodying the principles of the present invention isshown in thedrawings to illustrate the presently preferred embodiment ofthe present invention.

The tensioning unit 1 embodies, in general, an elongated supportingframe 2 on which is mounted a fluid-actuated unit 3, with thefluid-actuated unit 3 operatively connected to an elongatedcable-gripping member, in the form of a chuck 4- for reciprocating thechuck 4 longitudinally of the supporting frame 2.

The supporting frame 2 includes two substantially fiat,rectangular-shaped, end plates 5 and 6 disposed in parallel relation toeach other, and two elongated, substantially straight side rods 7 and 2'extending between respective end portions of the end plates 5 and 6 insubstantially parallel relation to each other. The end plates 5 and 6and the side rods '7 and 8 may be made of any suitable material such as,for example, steel, and may be suitably secured together such as, forexample, by welding.

The fiuid-actuated unit 3 includes an elongated cylinder 9 havingcylinder heads 10 and 11 mounted on the respective opposite end portionsthereof. The cylinder heads it) and 11 are held on the cylinder 9 by tiebolts 12 extending between the cylinder heads it? and 11 radiallyoutwardly of the cylinder 9.

The cylinder head 11 includes an inner wall 13, an outer wall l4, and anupper wall 15. The cylinder head 111 is hollow, and the cylinder 9extends through the inner wall 13 thereof, in threaded engagementtherewith, into the cylinder head 11, terminating in inwardly spacedrelation to the outer Wall 14. The outer wall 14 is imperferate.

The cylinder head it includes an inner wall 16, an outer wall 17 and atop wall 13 and, like the cylinder head 11, is hollow. The other end ofthe cylinder 9 extends through the inner wall 16 in threaded engagementtherewith, and terminates in inwardly spaced relation to the outer wall17 An end plate 119, which is preferably of the same size and shape asthe end plate 6 of the supporting frame 2, is secured to the outer faceof the end wall 1'7 of the cylinder head ill in parallel juxtapositionthereto. The plate 19 is of such size that the ends thereof projectoutwardly beyond the cylinder head It and the end plate 19 is secured tothe outer face of the end plate 6 of the supporting frame 2 in paralleljuxtaposition thereto by suitable securing members such as bolts 2% Thefluid-actuated unit 3 includes the usual piston 21 slidably mounted inthe cylinder for reciprocation longitudinally thereof. The piston 21includes an end portion 22 which extends outwardly through the cylinderh ad it and the end plates 6 and l? in longitudinal alignment with thecylinder 9. The end portion 22 of the piston 21 extends along thelongitudinal center line of the frame 2 and has a supporting member 23mounted on the free end thereof.

The supporting member 23 is substantially rectangular in shape, andincludes two substantially flat, rectangularshaped end walls 24 and :25disposed in parallel spaced relation to each other. It also includes twosubstantially flat, rectangular-shaped side Walls 26 and 27 extendingbetween respective end portions of the end walls 2% and :25 in parallelspaced relation to each other. The supporting member 23 is open at thetwo sides thereof which extend perpendicular to the side Walls 26 and27. The

t t 3 free end of the end portion 22 of the piston 21 extends throughthe end wall 25 of supporting member 23 between the side walls 26 and27, and the supporting member 23 is secured thereto by suitable meanssuch as, a nut 28.

A round abutment member 29 having a flat outer face 30 and a flat innerface 31 disposed in substantially parallel spaced relation to eachother, is secured to the outer face of the end plate of the supportingframe 2 in centered relation thereto, with the inner face 31 of theabutment member 29 disposed'in parallel juxtaposition to the outer faceof the end plate 5, FIGS. 1, 2, and 5. An outwardly opening slot 32extends radially outwardly through the abutment member 29 from theradial center thereof, and two other slots 33 and 34, corresponding insize and shape to the slot 32, extend through the end wall 5 of theframe 2 and the end wall 24 of the supporting member '23 respectively,in alignment with the slot 32 for a purpose which will be discussed ingreater detail presently.

The elongated chuck 4, for releasably gripping a cable to be tensioned,is mounted in the supporting member 23 in laterally centered relationthereto between the end wall 24 and the end 22 of the piston 21. Thechuck 4 may be secured in position in :the supporting member 23 by anysuitable means, but I prefer to releasably secure it in the supportingmember '23 by clamping it between the nut 23 and the end wall 24, FIG.2, with a sufficiently tight fit that it is necessary to tap the chuckinto position with a hammer.

The chuck 4 includes a tubular housing 36 having a substantiallycylindrical-shaped bore 37 in one end 38 thereof, FIGS. 9 and 10, and asubstantially frusto-conicalshaped bore 39 extending from the bore 37longitudinally through the housing 36 and opening outwardly through theother end it) thereof. The side Walls of the bore 3-9 slope inwardlyaway from the bore 37 at a relatively small acute angle, preferably inthe order of seven degrees.

Three elongated clamping jaws 41, 42, and 43, which are arcuate intransverse cross-section, are sl-idably mounted in the bore 39 inside-by-side relation to each other, FIGS. 8, 9, and 10. Each of thejaws 41-43 includes a narrow end face 44 and a wider end face 45disposed in spaced parallel relation to each other, with an innerlongitudinal face 46 extending between the end faces 44 and 45 insubstantially perpendicular relation thereto. Each of the jaws 41-43also includes an outer face 47, which slopes outwardly from the end face44- to the end face 45 thereof at the same angle as the outward slope ofthe side walls of the bore 39. The clamping jaws 41- 43 are mounted inthe bore 39 of the housing 36 in armate alignment with each other inposition to afford a tapered, three-piece clamping element 48, with thejaws d ll-43 disposed annularly around the outer periphery of the bore39.

The jaws 41-43 are of shorter length than the length of the bore 39, andthe clamping element 48 is reciprocable within the bore 39 from aposition wherein the end 7 l bore 4% is of considerably larger diameterthan the diameter of the cable to be tensioned by my novel tensioningunit .1, and when the clamping element 43 moves outwardly toward theaforementioned outermost position thereof, the bore 49 is reduced indiameter to such an extent that the clamping jaws 41-43 are disposed inposition to firmly grip any such cable disposed in the bore 49.

A plug 50 having an enlargedhead 51, from one side of which a threadedshank 52 extends, is mounted on the end 38 of the housing 36 with theshank 52 threaded into the bore 37. An opening 53, which preferably isat least of the same diameter as that of the bore t9 in the clampingelement 48 when the latter is fully expanded in the housing 36, extendslongitudinally through the shank 52 and the cap 51. The head 51 of theplug 51 is preferably of the same transverse cross-sectional size as thehousing 36, and the .outer surface thereof may be suitably rough- 7 enedsuch as, for example, by knurling, to facilitate the faces 44 thereofare disposed in uniplanar relation to the s end face 40 of the housing36, as shown in FIG. 9, and a position wherein the end faces 45 of thejaws, 41-43 are disposed in uniplanar relation to the inner end of thebore 39, as shown in FIG. 10. The arcs of the clamping jaws ell-43 areof such length that when the jaws 4143 are disposed in theaforementioned outer position, wherein the faces 44 thereof are disposedin uniplanar relation to the end wall 49 of the housing 36, space isstill afforded between the adjacent jaws 41:43, FIG. 8.

With this construction, it will be seen that the clamping element 48 isaiforded with a central bore 49, which extends longitudinallytherethrough, and which is progressively reduced in diameter as theclamping element :48 moves outwardly from the position shown in FIG. 1()toward the outer position shown in FIG. 9. The clamping insertion andremoval of the plug 5!).

A compression coil spring is mounted in the housing 36 of the chuck 4between the plug 50 and the clamping element 48, inposition to, at alltimes, yieldingly urge the clamping element 48 toward the aforementionedoutermost position shown in FIG. 9. The internal diameter of the spring75 is substantially larger than the diameter of the bore 53, and thespring 75 is of such outside diameter as to insure that'the spring 75 isat all times spaced radially outwardly of the bore 53. i

An elongated, substantially trough-shaped releasing member 54 is mountedin the slot 34 in the end plate 5 of the supporting frame 2 in inwardlyprojecting relation thereto, FIG. .4. The internal arch of the releasingmember 54 is of the same size and shape as the inner end portions of theslots 3 2-3-4, FIG. 5, and the outer arch of the releasing member 54- isof such a size that the releasing member 54 may fit into the bore 33 inthe end 4!! of the housing 36 of the chuck ;4 with a relatively snug,but freely slidable fit, for a purpose which will be discussed ingreater detail presently. 7

Two coupling members 71 and 72 are mounted in the top walls 18 and 15 ofthe cylinder heads 10-and'1 1, respectively, and are in communicationwith the hollow interiors of the cylinder heads 10 and '11. The otherends of the connecting members 71 and 72 may be connected Iby suitableconduit means such as, for example, hoses 7-3 and 74, respectively, to asuitable, controlled source (not shown) of working fluid such as, forexample, a source of hydraulic fluid such as, for example, a hydraulicpump having suitable valves associated therewith. By alternately feedingthe hydraulic fluid into the hoses 73 and 74, and exhausting the otherhoses 74 and 73, respectively, to sump, thepiston 21 may be caused toreciprocate in the cylinder 9 .in'a manner well known in the art.

Such reciprocation of the piston 21 is effective to reciprocate thesupporting member 23 and, therefore, the chuck 4 between a positionwherein the end wall 24 of the supporting member 2-3 is disposed inclosely adjacent relation to the end plate 5 of the supporting frame 2,as shown in FIG. 2, and a position wherein the supporting member 23 isdisposed in inwardly spaced relation to the end plate 5, asshown in FIG.4-. When the supporting member 24 is disposed in" the outermostposition, shown in FIG; 2, the releasing member 54 extends through theslot 34 int-o the outer end of the bore 39 in the housing 36 of thechuck 4, in which position it is elfective to hold the clamping element48 in fully retracted position, as shown in FIG. 10. When the supportingmember 23 is disposed in an inwardly disposed position, such as thatshown in FIG. 4, the supporting member 23 is disposed in inwardly spacedrelation relative to the releasing member 54, so that the latter isineitective to holdthe clamping element 48 in retracted position in thehousing 36 of the chuck 4, and the clamping element 48 is free to moveoutwardly under the urging of the spring '75 toward the outermostposition thereof shown'in FIG. 9. Thus, it

will be seen that during reciprocation of the supporting member 23, andtherefore, the chuck 4 with the piston 21 between the positions shown inFIGS. 2 and 4, the clamping element 48 is alternately pushed inwardly bythe releasing member 54 into the housing 36 to thereby permit expansionof the bore 4% therein, and moved outwardly, under the urging of thespring '75 in the bore 39 of the housing 36 to thereby reduce the sizeof the bore 49. As will be discussed in greater detail presently, thisaffords automatic operation for clampingly engaging, and releasing, acable to be tensioned in my novel tensioning unit 1, during operation ofthe latter.

In FIG. 1 my novel tensioning unit 1 is shown in op erative positionrelative to a form 55 for producing prestressed concrete 56 having aplurality of cables therein, two such cables 57 and 62 being showntherein. The form 55 and the concrete 56 are of a type which are wellknown in the art, and the showing thereof in FIG. 1 is fragmentary, thisbeing sufficient for an understanding thereof by those skilled in theart. It will be appreciated by those skilled in the art that the form 55may be of any suitable type well known in the art, the form 55 shown inFIG. 1 including two outer side walls 53 and 59 disposed insubstantially parallel spaced relation to each other, and two inner sidewalls 61 and 62 disposed in substantially parallel spaced relation toeach other between the side walls 58 and 59, and in inwardly spacedparallel relation to the latter. It will be understood that suitablesupporting members and bracing members, not shown, will be attached tothe walls 58-61 to hold the walls 5861 in the aforementioned operativepositions relative to each other.

In the formation of concrete 56 of the type shown in FIG. 1, cables suchas the cables 57 and 62 are first inserted through the walls 58-61 inproper position in the form 55. A plurality of suitable holding devices63 may then be secured to the ends of the cables 57 and 62 projectingoutwardly from the wall 58 of the form 55 in position to hold the cables57 and 62 against an inward pull thereon. If desired, the holdingdevices 63 may be identical in construction to the chuck 4, and if suchunits are used, the ends 40 thereof would be dis posed against the outerface of the wall 58, with the cables 57 and 62 extending through theholding devices 63. Thereafter, suitable holding devices 64 may besecured to the ends of the cables 57 and 62 projecting outwardly fromthe side wall 59 of the form 55 in position to hold the tension 011 therespective cables 57 and 62 after the tension has been applied thereto.If desired, these holding units 64 may also be identical in constructionto the chuck 4, and if such units are used, the ends 40 thereof would bedisposed in engagement with the outer face of the side wall 5? with thecables 57 and 62 extending through the chucks 64, and with free endportions 65 of the cables 57 and 62 extending outwardly from the holdingunits 64.

In the operation of my novel tensioning unit 1, the free end of thecable to be tensioned such as, for example, the free end 65 of the cable57, may be inserted through the slots 3244 into the bore 49 in theclamping jaw 48, with the supporting member 23 disposed in the fullyoutwardly disposed position shown in FIGS. 1, 2 and 10, wherein thereleasing member 54 is eifective to hold the clamping unit 48 in fullyretracted position, as shown in FIG. 10. If desired, the free end 65 ofthe cable 57 may be extended entirely through the chuck 4. However, thisis not essential, and it is merely necessary that the free end 65 extendinto the chuck 4 a sufiicient distance that it may be effectivelygripped by the clamping element 48 during an operation of the unit 1.

Thereafter, the tensioning unit 1 may be moved into position wherein theouter face 30 of the abutment member 29 is disposed in abuttingengagement with the outer end of the holding device 64 on the cable 57,and the fluid-actuated device 3 may then be actuated to cause the piston21 to move away from the end plate 5 of the supporting frame 2. Suchmovement of the piston 21 is effective to correspondingly move thesupporting member 23 and the chuck 4 to thereby move the chuck 4 intoinwardly spaced relation to the releasing member 54. Such movement ofthe chuck 4 frees the clamping elemerit 48 for movement outwardlythrough the bore 3? in the chuck 4 under the urging of the spring 75,into frictional engagement with the outer peripheral surface of the freeend of the cable 57. Thereafter, continued movement of the chuck 4 insuch direction is effective to cause the clamping jaws 41-43 to increasetheir clamping pressure on the cable 57 and thereby firmly grip thelatter. With the free end 65 of the cable 57 thus firmly gripped in thechuck 4, continued movement of the chuck 4 to the right, as viewed inFIG. 2, is effective to tension the cable 57, the cable 57 being pulledthrough the hold ing member 64 mounted thereon.

After the cable 57 has been tensioned to the desired extent, theoperation of the fluid-actuated unit 3 may be reversed to thereby causethe piston 21 and the supporting member 2.3 to move to the left, asviewed in FIGS. 2 and 4, and as the supporting member 23 moves towardits normal at-rest position, adjacent to the end plate 5 of thesupporting frame 2, shown in PEG. 2, the releasing member 54 enters thebore 39 in the chuck 35 and moves the lamping element 48 inwardly intothe enlarged portion of the bore 39 in the housing 56 to thereby freethe chuck 4 from gripping engagement with the end portion 65 of thecable 57. However, it will be remembered that the holding unit 64 ismounted on the free end portion 65 of the cable 57 in holding relationthereto, so that release of that free end portion 65 by the chuck 4 doesnot release the tension on the cable 57 between the side walls 58 and 59of the form 55, the tension on that portion of the cable 57 being heldby the holding units 63 and 64 attached thereto.

After tensioning one of the cables, such as the cable 57, the tensioningunit 1 may be withdrawn therefrom, and the cycle of operaion repeated onthe next cable which is to be so tensioned, such as, for example, thecable 62. This operation may be repeated on each cable to be tensionedin the form 55, and after all of the cables have been properlytensioned, the concrete 56 may be poured into the form 55 between theside walls 66 and 61. After the concrete 56 has set to the desiredextent, the tension on the cables between the holding devices 63 and 64may be released in any suitable manner such as, for example, by cuttingthe cables, such as the cables 57 and 62 between the walls 53 and 66,and the walls 59 and 61, respectively. This operation releases thetension on the holding units 63 and 64, and they may then be releasedfrom the free end portions of the cables on which they are mounted. Thefinished concrete 56 with the tensioned cables, such as the cables 57and 62, therein may then be removed from the form 55.

It will be appreciated by those skilled in the art that although theopenings 32-34 are shown herein as slots, and the releasing member 54 isshown as trough-shaped, the openings 3244 may be different shape, suchas round openings, and the releasing member 54 may be of differentshape, such as tubular, with the end of the cable to be tensioned beinginserted and withdrawn axially therethrough.

From the foregoing it will be seen that the present invention affords anovel and practical tensioning unit for tensioning cables in concreteforms, and the like.

Also, it will be seen that the present invention aifords a noveltensioning unit of the aforementioned type which may be constructed insuch a size, and of such a weight that it may be readily transport-edand easily handled.

In addition, it will be seen that the present invention affords a noveltensioning unit which may be quickly and easily attached to and releasedfrom such a cable in a novel and expeditious manner.

success Also, it will be seen that the present invention'aifords anoveltensioning unit which is practical and efficient in operation and may bereadily and economically produced commercially.

Thus, While I have illustrated and described the preferred embodiment ofmy invention, it is to be understood that this is capable of variationand modification and I therefore do not wish to be limited to theprecise details set forth, but desire to avail myself of such changesand alterations as fall within the purview of the following claims.

I claim:

1. An apparatus for tensioning cables, comprising, in combination,

(1) a fluid actuated driving unit including,

(a) a rear frame assembly (b) a cylinder supported in said frameassembly (c) a piston reciprocable in said cylinder (d) front and rearend cylinder heads on said cylinder, including a front opening in saidfront end cylinder head,

(e) a forwardly extending piston rod attached to said piston andextending through said opening, and

(f) means for supplying driving fluid to either end of said cylinder forreciprocably driving said piston and said rod,

(2) a front frame and chuck holder assembly includ- (a) rigid membersforming the sides of said front frame, and disposed across said membersand forming the front end portion of said frame,

(b) a rigid front plate including a front surface portion for abuttingthe rear of a chuck disposed on a cable to be tensioned, and forpreventing rearward movement of said chuck during tensioning of thecable, while applying a tensioning force to said cable, and

(c) a chuck holder attached to said piston rod and reciprocable betweensaid front end plate and said front cylinder head, said chuck holderincluding a cable receiving slot in the front face thereof.

2. An apparatus as defined in claim 1 which includes a cut-out portionin said chuck holder for allowing chuck-releasing means to extendtherethrough for engaging and releasing the movable jaws of a chuck heldin said chuck holder.

3. An apparatus as defined in claim 1 in Which said rigid front platealso includes chuck-releasing means disposed on the inner side of saidfront plate and extending rearwardly therefrom.

4. An apparatus as defined in claim 1 in which said chuck holderincludes a cut-out portion for allowing chuck-releasing means to extendtherethrough for engaging and releasing the movable jaws of a chuck heldin said chuck holder, and in which said rigid front plate includeschuck-releasing means disposed on the inner side of said front plate andadapted to extend rearwardly therefrom and through said cut-out portionwhen said chuck holder is in a forward position.

5. 'An apparatus for tensioning cable in a concrete prestressingoperation, said apparatus comprising in combination,

(1) a fluid cylinder including two cylinder heads therefor the frontcylinder head having an opening therein,

(2) said heads each having means for thereinto,

(3) a reciprocaoly cylinder,

(4) means for supplying'fluid to either end of said cylinder toreciprocate said .piston,

(5) a reciprocable rod attached to said piston and extending throughsaid opening in said front cylinder head, a

(6) a generally rectangular reciprocable open-sided chuck holder fixedlyattached to said rod, said holder including a cable receiving slottherein,

(7) an autoiuatieally-actuatable cable chuck mounted in said chuckholder and adapted tonormally receive and automatically frictionallyengage by movement thereof a cable to, be tensioned,

(8) said cable being tensioned by movement of said reciproca lc holderand automatic chuck in a first direction upon the supply of fluid to agiven end of said cylinder, and released by'said chuck automatically bymovement in the opposite direction,

(9) forwardly extending frame means within which at least said reciprocale chuck holder and said automaticallyectuatabie chuck travel, saidframe means including side rails and end walls, one end wall secured toone face of the front cylinder head, the other end well including acable receiving slot therein in alignment with said slot in said chuckholder,

(a) said other end wall of the frame means ineluding a portion thereofnormally abutting the rear of a cable holding unit in normal engagementwith said cable being tensioned, said porticn preventing movement ofsaid holding unit during reciprocation of said reciprocable chuck holderand automatic chuck whereby the desired tension of said cable isachieved by reciprocation of said chuck holder andautomatically-actuatable cable chuck.

admitting fluid movable piston disposed in said References Cited bytheExaminer UNITED STATES PATENTS FOREIGN PATENTS 7/ 5 6 France.

3 5 6 Germany.

7/ 5 6 Great Britain. 8/ 49 Italy.

OTHER REFERENCES Supreme Products Corp. Pamphlet No. 368, SupremeStrandChucks, 4 pages.

WILLIAM FELDMAN, Primary Examiner. DONLEY J. STOCKING, Examiner.

1. AN APPARATUS FOR TENSIONING CABLES, COMPRISING, IN COMBINATION, (1) AFLUID ACTUATED DRIVING UNIT INCLUDING, (A) A REAR FRAME ASSEMBLY (B) ACYLINDER SUPPORTED IN SAID FRAME ASSEMBLY (C) A PISTON RECIPROCABLE INSAID CYLINDER (D) FRONT AND REAR END CYLINDER HEADS ON SAID CYLINDER,INCLUDING A FRONT OPENING IN SAID FRONT END CYLINDER HEAD, (E) AFORWARDLY EXTENDING PISTON ROD ATTACHED TO SAID PISTON AND EXTENDINGTHROUGH SAID OPENING, AND (F) MEANS FOR SUPPLYING DRIVING FLUID TOEITHER END OF SAID CYLINDER FOR RECIPROCABLY DRIVING SAID PISTON ANDSAID ROD, (2) A FRONT FRAME AND CHUCK HOLDER ASSEMBLY INCLUDING, (A)RIGID MEMBERS FORMING THE SIDES OF SAID FRONT FRAME, AND DISPOSED ACROSSSAID MEMBERS AND FORMING THE FRONT END PORTION OF SAID FRAME, (B) ARIGID FRONT PLATE INCLUDING A FRONT SURFACE PORTION FOR ABUTTING THEREAR OF A CHUCK DISPOSED ON A CABLE TO BE TENSIONED, AND FOR PREVENTINGREARWARD MOVEMENT OF SAID CHUCK DURING TENSIONING OF THE CABLE, WHILEAPPLYING A TENSIONING FORCE TO SAID CABLE, AND (C) A CHUCK HOLDERATTACHED TO SAID PISTON ROD AND RECIPROCABLE BETWEEN SAID FRONT ENDPLATE AND SAID FRONT CYLINDER HEAD, SAID CHUCK HOLDER INCLUDING A CABLERECEIVING SLOT IN THE FRONT FACE THEREOF.